I have the 500 v1 and 600 v2 and am likely to buy the 200-400 and sell the 500 v1.I am just waiting for someone/somewhere to test it objectively as opposed to qualitatively. Hopefully the digitalpicture.com.

Several times while shooting wolves in the last 6 months (which you have to be really lucky to have the opportunity for) the wolf has decided to come to close and pose which has caused a mad scramble from 600/1.4 on 7d to 70-200 on 5diii. The 100-400 is a great lens but f5.6 on just makes the exposure too long. And 2 years ago I blew it with some young wolves with 500mm - too tight or too close all in the same 5 minutes.

And juggling my 1.4x with a big lens is scary for bodies and lens.

This guy just ended up being too tight. And the 100-400 would not have been as nice for such a great shot.

I have the 500 v1 and 600 v2 and am likely to buy the 200-400 and sell the 500 v1.I am just waiting for someone/somewhere to test it objectively as opposed to qualitatively. Hopefully the digitalpicture.com.

Several times while shooting wolves in the last 6 months (which you have to be really lucky to have the opportunity for) the wolf has decided to come to close and pose which has caused a mad scramble from 600/1.4 on 7d to 70-200 on 5diii. The 100-400 is a great lens but f5.6 on just makes the exposure too long.

And juggling my 1.4x with a big lens is scary for bodies and lens.

This guy just ended up being too tight. And the 100-400 would not have been as nice for such a great shot.